Análise viscoelástica de estruturas laminadas mediante emprego da inversao numérica da transformada de Laplace

Este trabalho focaliza a análise viscoelástica de estruturas laminadas em material compósito de matriz polimérica, propondo o emprego de métodos de inversa0 numérica da transformada de Laplace numa formulacao adaptada ao método dos elementos finitos. Nesta abordagem alternativa,as equacóes constitutivas viscoelásticas, formuladas no plano complexo da variável de transformacáo S , reduzem o problema a urna análise elástica equivalente. As solu~óesc omplexas sáo entiio retornadas ao plano físico para o valor de tempo desejado, dispensando processos incrementais. Exemplos de aplicaqóes siio executados comparando-se os resultados do Método da Transformada de Laplace com o Método das Variáveis de Estado que trata o problema viscoelástico de forma incremental.The viscoelastic analysis of laminated structures of polymeric matrix composite materials using Laplace transform is the objective of this work. The inverse of the Laplace transform is carried out using numerical methods adapted to a finite element method formulation. In this alternative aproach, as the constitutive equations are formulated on the complex plane in the transformation variable 'S', the viscoelasti~problemre duces to an equivalent elastic one. The complex solutions are then sent back to the physical plane for the desired time value, dispensing incremental processes. Examples of aplications compairing results obtained with the Laplace Transformation Method and the State Variables Method (that treats the viscoelastic problem in an incremental form) are presented.Peer Reviewe

Effects of the consumption of polyunsaturated fatty acids on the oxidative status of adult dogs

The present study evaluated the alterations of the oxidative stress markers in adult dogs fed with high levels of PUFA from the mixture of soybean oil enriched with docosahexaenoic acid (DHA) and supplemented with a natural algae-based antioxidant (AOX). Twelve healthy adult (2 years old) Beagle dogs (6 males and 6 females, 11.20 ± 1.92 kg BW), were distributed in 2 completely randomized blocks design and fed with 4 experimental diets coated with 2 lipid sources: saturated (13% bovine tallow) or unsaturated (13% soybean oil enriched with DHA), supplemented or not with 500 mg of AOX for 4 wk, intercalated with a 4 wk adaptation period. Blood samples were collected on days 0, 15, and 30 of each block. Glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), sulfhydryl group (SH), protein carbonylation, thiobarbituric acid reactive substances (TBARS), and total reactive antioxidant potential (TRAP) were evaluated in the serum, while GSH-Px, SOD, glutathione S-transferase (GST), catalase (CAT), SH, and TBARS were measured in erythrocytes. There was no significant difference in most of the oxidative markers evaluated. In contrast, GST activity in erythrocytes was greater in the animals that consumed the diets coated with bovine tallow compared to dogs that consumed diets coated with soybean oil enriched with DHA (P < 0.05). Serum from dogs fed on diets supplemented with AOX presented greater TRAP values (P < 0.05). These data demonstrate that the concentrations of unsaturated fatty acids used in the diets for dogs were not sufficient to cause large changes in the oxidative status. It was not possible to evaluate the efficiency of the natural antioxidant in maintaining the oxidative balance of the animals as it appears that the oxidative status of the dogs was not challenged by the unsaturated diets. Our findings also suggest that dogs, as descendants from carrion carnivores, may have some natural protection against oxidatio

Shielding AZ91D-1%Ca from corrosion through ultrasound melt treatment: a study for stent design

Magnesium-based materials show great potential for producing biodegradable stents, but their high corrosion rates are a roadblock. This study investigates whether ultrasound melt treatment can change the corrosion response of an extruded AZ91D-1.0%Ca (wt.%) in Earle's Balanced Salt Solution by tailoring the intermetallics' morphology in the as-extruded state. The results showed that the wires from ultrasound-treated ingots corroded faster than non-treated ones in immersion for up to 6 hours. This trend shifted for longer periods, and ultrasound-treated material showed lower corrosion rates and uniform corrosion, while the non-treated material displayed localized corrosion signs. Tensile testing of the wires demonstrated that immersion in EBSS lowered the tensile strength and elongation at fracture due to material degradation, regardless of the processing route. Nonetheless, this decline was sharper in the non-treated material. These findings suggest that ultrasound melt processing can be a promising method for improving the corrosion resistance of magnesium-based materials, paving the way for their use in manufacturing biodegradable stents.This work was supported by Portuguese FCT under the project UIDB/04436/2020, the doctoral grant PD/BD/140094/2018 and SFRH/BD/145285/2019

Multiplus: a modular high-performance multiprocessor

The MULTIPLUS project is currently under development at NCE/UFRJ, Brazil, aims at the study of parallel processing problems in MIMD environments. The project includes the development of a parallel shared-memory architecture and a UNIX-like operating operating system called MULTIPLIX. The MULTIPLUS achitecture uses an inverted n-cube multistage network to interconnect clusters of processing nodes designed around a double-bus system. As a consequence, the architecture is partitionable and modular. It cas easily and efficiently supportconfigurations ranging from workstations to powerful parallel supercomputers with up to 2048 processing nodes. The MULTIPLix operating system provides MULTIPLUS with an efficient computing environment for parallel scientific applications. MULTIPLIX uses the concept of thread, implements busy-waiting synchronization primitives very efficiently and carefully considers data locality and scientific processing requirements in the policies adopted for memory management and thread scheduling.O projeto MULTIPLUS, que está atualmente em desenvolvimento no NCE/UFRJ, objetiva o estudo de problemas de processamento paralelo em ambiente MIMD. O projeto inclui o desenvolvimento de uma arquitetura paralela com memória compartilhada e um sistema operacional tipo UNIX chamado MULTIPLIX. A arquitetura do MULTIPLUS usa uma rede de interconexão multiestágio do tipo n-cubo invertido para interligar clusters de nós de processamento projetados em torno de um sistema de barramento duplo. Como consequência a arquitetura é patrocinável e modular. Ela pode suportar eficientemente configurações cobrindo um espectro que vai desde estações de trabalho até poderosos supercomputadores contendo 2048 nós de processamento trabalhando em paralelo. O sistema operacional MULTIPLIX provê o MULTIPLUS com um ambiente eficiente de computação para aplicações científicas paralelas.O MULTIPLIX usa o conceito de "thread", implementa primitivas de sincronização de espera ocupara muito eficientemente e considera fortemente aspectos de localidade dos dados e requisitos de processamento científico nas políticas adotadas para gerenciamento de memória e escalonamento de "threads"

Annotated checklist of the birds of Brazil by the Brazilian Ornithological Records Committee-second edition

An updated version of the checklist of birds of Brazil is presented, along with a summary of the changes approved by the Brazilian Ornithological Records Committee's Taxonomy Subcommittee since the first edition, published in 2015. In total, 1971 bird species occurring in Brazil are supported by documentary evidence and are admitted to the Primary List, 4.3% more than in the previous edition. Eleven additional species are known only from undocumented records (Secondary List). For each species on the Primary List, status of occurrence in the country is provided and, in the case of polytypic species, the respective subspecies present in Brazilian territory are listed. Explanatory notes cover taxonomic changes, nomenclatural corrections, new occurrences, and other changes implemented since the last edition. Ninety species are added to the Primary List as a result of species descriptions, new occurrences, taxonomic splits, and transfers from the Secondary List due to the availability of documentation. In contrast, eight species are synonymized or assigned subspecific status and thus removed from the Primary List. In all, 293 species are endemic to Brazil, ranked third among the countries with the highest rate of bird endemism. The Brazilian avifauna currently consists of 1742 residents or breeding migrants, 126 seasonal non-breeding visitors, and 103 vagrants. The category of vagrants showed the greatest increase (56%) compared to the previous list, mainly due to new occurrences documented in recent years by citizen scientists. The list updates the diversity, systematics, taxonomy, scientific and vernacular nomenclature, and occurrence status of birds in Brazil.Peer reviewe

The Genome of Anopheles darlingi, the main neotropical Malaria vector

Anopheles darlingi is the principal neotropical malaria vector, responsible for more than a million cases of malaria per year on the American continent. Anopheles darlingi diverged from the African and Asian malaria vectors ∼100 million years ago (mya) and successfully adapted to the New World environment. Here we present an annotated reference A. darlingi genome, sequenced from a wild population of males and females collected in the Brazilian Amazon. A total of 10 481 predicted protein-coding genes were annotated, 72% of which have their closest counterpart in Anopheles gambiae and 21% have highest similarity with other mosquito species. In spite of a long period of divergent evolution, conserved gene synteny was observed between A. darlingi and A. gambiae. More than 10 million single nucleotide polymorphisms and short indels with potential use as genetic markers were identified. Transposable elements correspond to 2.3% of the A. darlingi genome. Genes associated with hematophagy, immunity and insecticide resistance, directly involved in vector–human and vector–parasite interactions, were identified and discussed. This study represents the first effort to sequence the genome of a neotropical malaria vector, and opens a new window through which we can contemplate the evolutionary history of anopheline mosquitoes. It also provides valuable information that may lead to novel strategies to reduce malaria transmission on the South American continent. The A. darlingi genome is accessible a